
/*
 * Copyright (c) 1987, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#if defined(_MSC_VER) || defined(__MINGW32__)
# include <io.h>
# include <process.h> // for getpid()
# include <direct.h> // for mkdir()
# if defined(_MSC_VER)
/* MSVC is missing a few definitions from sys/types and sys/stat */
typedef int pid_t;
#  define S_ISDIR(m)  (((m) & _S_IFMT) == _S_IFDIR)
# endif
#else
# include <unistd.h> // for getpid()
#endif
#include <errno.h>
#include <stdio.h>

static int
do_mkdtemp (char *path)
{
  char *start, *trv;
  struct stat sbuf;
  pid_t pid;

  /* To guarantee multiple calls generate unique names even if
     the file is not created. 676 different possibilities with 7
     or more X's, 26 with 6 or less. */
  static char xtra[2] = { 'a', 'a' };
  int xcnt = 0;

  pid = getpid ();

  /* Move to end of path and count trailing X's. */
  for (trv = path; *trv; ++trv)
    if (*trv == 'X')
      xcnt++;
    else
      xcnt = 0;

  /* Use at least one from xtra.  Use 2 if more than 6 X's. */
  if (*(trv - 1) == 'X')
    *--trv = xtra[0];
  if (xcnt > 6 && *(trv - 1) == 'X')
    *--trv = xtra[1];

  /* Set remaining X's to pid digits with 0's to the left. */
  while (*--trv == 'X')
    {
      *trv = (char)((pid % 10) + '0');
      pid /= 10;
    }

  /* update xtra for next call. */
  if (xtra[0] != 'z')
    xtra[0]++;
  else
    {
      xtra[0] = 'a';
      if (xtra[1] != 'z')
        xtra[1]++;
      else
        xtra[1] = 'a';
    }

  /*
   * check the target directory; if you have six X's and it
   * doesn't exist this runs for a *very* long time.
   */
  for (start = trv + 1;; --trv)
    {
      if (trv <= path)
        break;
      if (*trv == '/')
        {
          *trv = '\0';
          if (stat (path, &sbuf))
            return (0);
          if (!S_ISDIR (sbuf.st_mode))
            {
              errno = ENOTDIR;
              return (0);
            }
          *trv = '/';
          break;
        }
    }

  for (;;)
    {
#if !defined(_MSC_VER) && !defined(__MINGW32__)
      if (mkdir (path, 0700) >= 0)
#else
      if (_mkdir (path) >= 0)
#endif
        return (1);
      if (errno != EEXIST)
        return (0);

      /* tricky little algorithm for backward compatibility */
      for (trv = start;;)
        {
          if (!*trv)
            return (0);
          if (*trv == 'z')
            *trv++ = 'a';
          else
            {
              if (*trv >= '0' && *trv <= '9')
                *trv = 'a';
              else
                ++*trv;
              break;
            }
        }
    }
 /*NOTREACHED*/}

char *
mkdtemp (char *path)
{
  return (do_mkdtemp (path) ? path : (char *) NULL);
}
